This invention relates to bicycles and more particularly to propulsion means for driving the bicycle and also to speed change means associated with the propulsion means.
Conventional bicycles are driven by pedals connected by cranks to a sprocket which is connected to gear means on the back wheel by a chain drive. The cranks are rotated by the operator and the chain transmits the force to the gear means of the rear wheel to turn the wheel. Thus, when the cranks are turned by means of the pedals, the sprocket and gears are mutually driven at the same time. The changing of gears for speed changes is accomplished with some difficulty and it is necessary to restrain the gear during the change.
The present invention provides a novel propulsion means and speed change means which is easy to attain.